The present invention relates to chemical compounds that inhibit MKNK1 kinase (also known as MAP Kinase interacting Kinase, Mnk1) and/or MKNK2 kinase (also known as MAP Kinase interacting Kinase, Mnk2). Human MKNKs comprise a group of four proteins encoded by two genes (Gene symbols: MKNK1 and MKNK2) by alternative splicing. The b-forms lack a MAP kinase-binding domain situated at the C-terminus. The catalytic domains of the MKNK1 and MKNK2 are very similar and contain a unique DFD (Asp-Phe-Asp) motif in subdomain VII, which usually is DFG (Asp-Phe-Gly) in other protein kinases and suggested to alter ATP binding [Jauch et al., Structure 13, 1559-1568, 2005 and Jauch et al., EMBO J25, 4020-4032, 2006]. MKNK1a binds to and is activated by ERK and p38 MAP Kinases, but not by JNK1. MKNK2a binds to and is activated only by ERK. MKNK1b has low activity under all conditions and MKNK2b has a basal activity independent of ERK or p38 MAP Kinase. [Buxade M et al., Frontiers in Bioscience 5359-5374, May 1, 2008]
MKNKs have been shown to phosphorylate eukaryotic initiation factor 4E (eIF4E), heterogeneous nuclear RNA-binding protein A1 (hnRNP A1), polypyrimidine-tract binding protein-associated splicing factor (PSF), cytoplasmic phospholipase A2 (cPLA2) and Sprouty 2 (hSPRY2) [Buxade M et al., Frontiers in Bioscience 5359-5374, May 1, 2008].
eIF4E is an oncogene that is amplified in many cancers and is phosphorylated exclusively by MKNKs proteins as shown by KO-mouse studies [Konicek et al., Cell Cycle 7:16, 2466-2471, 2008; Ueda et al., Mol Cell Biol 24, 6539-6549, 2004]. eIF4E has a pivotal role in enabling the translation of cellular mRNAs. eIF4E binds the 7-methylguanosine cap at the 5′ end of cellular mRNAs and delivers them to the ribosome as part of the eIF4F complex, also containing eIF4G and eIF4A. Though all capped mRNAs require eIF4E for translation, a pool of mRNAs is exceptionally dependent on elevated eIF4E activity for translation. These so-called “weak mRNAs” are usually less efficiently translated due to their long and complex 5′UTR region and they encode proteins that play significant roles in all aspects of malignancy including VEGF, FGF-2, c-Myc, cyclin D1, survivin, BCL-2, MCL-1, MMP-9, heparanase, etc. Expression and function of eIF4E is elevated in multiple human cancers and directly related to disease progression [Konicek et al., Cell Cycle 7:16, 2466-2471, 2008].
MKNK1 and MKNK2 are the only kinases known to phosphorylate eIF4E at Ser209. Overall translation rates are not affected by eIF4E phosphorylation, but it has been suggested that eIF4E phosphorylation contributes to polysome formation (i.e. multiple ribosome on a single mRNA) that ultimately enables more efficient translation of “weak mRNAs” [Buxade M et al., Frontiers in Bioscience 5359-5374, May 1, 2008]. Alternatively, phosphorylation of eIF4E by MKNK proteins might facilitate eIF4E release from the 5′ cap so that the 48S complex can move along the “weak mRNA” in order to locate the start codon [Blagden S P and Willis A E, Nat Rev Clin Oncol. 8(5):280-91, 2011]. Accordingly, increased eIF4E phosphorylation predicts poor prognosis in non-small cell lung cancer patients [Yoshizawa et al., Clin Cancer Res. 16(1):240-8, 2010]. Further data point to a functional role of MKNK1 in carcinogenesis, as overexpression of constitutively active MKNK1, but not of kinase-dead MKNK1, in mouse embryo fibroblasts accelerates tumor formation [Chrestensen C. A. et al., Genes Cells 12, 1133-1140, 2007]. Moreover, increased phosphorylation and activity of MKNK proteins correlate with overexpression of HER2 in breast cancer [Chrestensen, C. A. et al., J. Biol. Chem. 282, 4243-4252, 2007]. Constitutively active, but not kinase-dead, MKNK1 also accelerated tumor growth in a model using Eμ-Myc transgenic hematopoietic stem cells to produce tumors in mice. Comparable results were achieved when an eIF4E carrying a S209D mutation was analyzed. The 5209D mutation mimicks a phosphorylation at the MKNK1 phosphorylation site. In contrast, a non-phosphorylatable form of eIF4E attenuated tumor growth [Wendel H G, et al., Genes Dev. 21(24):3232-7, 2007]. A selective MKNK inhibitor that blocks eIF4E phosphorylation induces apoptosis and suppresses proliferation and soft agar growth of cancer cells in vitro. This inhibitor also suppresses outgrowth of experimental B16 melanoma pulmonary metastases and growth of subcutaneous HCT116 colon carcinoma xenograft tumors without affecting body weight [Konicek et al., Cancer Res. 71(5):1849-57, 2011]. In summary, eIF4E phosphorylation through MKNK protein activity can promote cellular proliferation and survival and is critical for malignant transformation. Inhibition of MKNK activity may provide a tractable cancer therapeutic approach.
Substituted thienopyrimidine compounds have been disclosed in prior art for the treatment or prophylaxis of different diseases:
WO 2010/006032 A1 (Duquesne University of the Holy Spirit) addresses tricyclic compounds as antimitotic agents. According to the general formula of claim 1, the tricycles inter alia comprise 5,6,7,8-tetrahydrobenzo[1]thieno[2,3-d]pyrimidines that may carry substituents at the carbocycle and one aromatic or heteroaromatic moiety at an optional 4-amino group. Furthermore, they may be unsubstituted at position 2 in the pyrimidine ring. However, the examples provided clearly differ from the compounds of the present invention. While the vast majority contains the C6 carbocycle completely unsaturated as aromatic ring, only two examples show a tetrahydrobenzo substructure in combination with a 4-amino group and in both cases the latter is bisubstituted by a phenyl and a methyl group. Furthermore, the specified compounds are with no exception pyrimidin-2-amines or 2-methyl-pyrimidines.
JP2007084494 (Oncorex Inc.) relates to PIM-1 inhibitors. One claim comprises 5,6,7,8-tetrahydrobenzo[1]thieno[2,3-d]pyrimidin-4-amines that can be monosubstituted at the amino group by optionally substituted phenyl. However, the optional substituents of phenyl are restricted to hydroxy, alkoxy or alkenyloxy. The tricyclic core does not show further substitutions. The only example of a direct substitution at the 4-amino group by phenyl is compound VII-2 with meta-methoxyphenyl.
WO 2002/088138 A1 (Bayer Pharmaceuticals Corporation) relates to PDE7b inhibitors and comprises 5,6,7,8-tetrahydrobenzo[1]thieno[2,3-d]pyrimidin-4-amines where the carbocycle and the 4-amino group may be optionally substituted by a wide range of substituents. The respective oxa, thia or aza analoga at position 7 with no further substituents at that ring are also claimed, the sulphur may be oxidized to sulphone and the nitrogen can be substituted. However, pyrid-4-yl in the 5,6,7,8-tetrahydrobenzo series and 3,4-dichlorophenyl and indazol-5-yl in the 6,9-dihydro-7H-pyrano series are the only examples with direct aromatic substitution at the 4-amino group.
WO 2005/010008 A1 (Bayer Pharmaceuticals Corporation) discloses 5,6,7,8-tetrahydrobenzo[1]thieno[2,3-d]pyrimidin-4-amines as proliferation inhibitors of A431 and BT474 cells which are model cell lines used in biomedical research. More specifically, A431 and BT474 cells are used in studies of the cell cycle and cancer-associated cell signalling pathways since they express abnormally high levels of the epidermal growth factor receptor (EGFR) and HER2, respectively. Substitution at the 4-amino group is limited to monosubstitution by either optionally substituted phenyl or optionally substituted indazolyl. The carbocycle may be substituted one or two times at position 7 by optionally substituted alkyl or alkenyl, by substituted carbonyl, hydroxy, optionally substituted amino or may be linked to the nitrogen of one or two saturated six membered rings optionally bearing a second heteroatom. Regarding the aromatic substituents at the 4-amino group, disclosed examples cover phenyl with a broad range of substituents and some indazol-5-yls but all are substituted at the nitrogen at position 1. Furthermore, all examples show an alkyl group in position 7 that is terminally further substituted by an amino group or hydroxyl group or in case of synthetic intermediates also by an ester function. Furthermore, as shown hereinafter, the compounds disclosed in WO 2005/010008 A1 are potent EGFR inhibitors but less effective MKNK inhibitors whereas the compounds of the present invention are potent MKNK inhibitors and less effective EGFR inhibitors. WO 2009/134658 (National Health Research Institutes) relates to inhibitors of Aurora kinase. The patent application generically covers tricyclic thieno[2,3-d]pyrimidin-4-amines with the third ring fused to the thiophene subunit. However, an optional aryl or heteroaryl substituent at the 4-amino group must carry a side chain involving a carbonyl, thiocarbonyl or iminomethylene group. The vast majority of more than 250 examples is formed by bicyclic 6,7-dihydrofuro[3,2-d]pyrimidin-4-amines that show in 4 cases a direct aromatic substitution at the 4-amino group but additionally substitution by two phenyl groups at the dihydrofuro subunit. None of the very few examples for tricyclic compounds shows direct substitution by an aromatic moiety at the 4-amino group.
WO 2006/136402 A1 and WO 2007/059905 A2 (Develogen AG) disclose thienopyrimidin-4-amines and their use for the prophylaxis and/or treatment of diseases which can be influenced by the inhibition of the kinase activity of Mnk1 and/or Mnk2. The 4-amino-group is substituted by a substituted phenyl group. The WO publications do not disclose any biological data.
WO 2010/023181 A1, WO 2011/104334 A1, WO 2011/104337 A1, WO 2011/104338 A1 and WO 2011/104340 A1 (Boehringer Ingelheim) relate to thienopyrimidin-4-amines for the prophylaxis and/or treatment of diseases which can be influenced by the inhibition of the kinase activity of Mnk1 and/or Mnk2. In case of the disclosed thienopyrimidin-4-amines there is no tetrahydrobenzo ring fused to the thienopyrimidine core. Additionally, the 4-amino group does not carry an indazol-5-yl substituent. In case of the compounds disclosed in WO 2010/023181 A1 the IC50 values vary between 0.035 μM and 0.68 μM with respect Mnk1, and between 0.006 μM and 0.56 μM with respect to Mnk2. In case of the compounds disclosed in WO 2011/104334 A1 the IC50 values vary between 1 nM and 9700 nM with respect to Mnk2. In case of the compounds disclosed in WO 2011/104337 A1 the IC50 values vary between 2 nM and 8417 nM with respect to Mnk2. In case of the compounds disclosed in WO 2011/104338 A1 the IC50 values vary between 8 nM and 58 nM with respect to Mnk2. In case of the compounds disclosed in WO 2011/104340 A1 the IC50 values vary between 3 nM and 5403 nM with respect to Mnk2. ALL WO publications contain the statement that the compounds described therein show improved solubility, are highly selective and show improved metabolic stability when compared to the compounds disclosed in WO 2006/136402 A1 and WO 2007/059905 A2 (Develogen AG, see above). However, besides the IC50 values discussed in this paragraph, there are no more data proving this statement.
The state of the art described above does not describe the specific substituted thienopyrimidine compounds of general formula (I) of the present invention as defined herein or a stereoisomer, a tautomer, an N-oxide, a hydrate, a solvate, or a salt thereof, or a mixture of same, as described and defined herein, and as hereinafter referred to as “compounds of the present invention”, or their pharmacological activity.
It has now been found, and this constitutes the basis of the present invention, that said compounds of the present invention have surprising and advantageous properties.
In particular, said compounds of the present invention have surprisingly been found to effectively inhibit MKNK1 kinase and may therefore be used for the treatment or prophylaxis of diseases of uncontrolled cell growth, proliferation and/or survival, inappropriate cellular immune responses, or inappropriate cellular inflammatory responses or diseases which are accompanied with uncontrolled cell growth, proliferation and/or survival, inappropriate cellular immune responses, or inappropriate cellular inflammatory responses, particularly in which the uncontrolled cell growth, proliferation and/or survival, inappropriate cellular immune responses, or inappropriate cellular inflammatory responses is mediated by MKNK1 kinase, such as, for example, haematological tumours, solid tumours, and/or metastases thereof, e.g. Leukaemias and myelodysplastic syndrome, malignant lymphomas, head and neck tumours including brain tumours and brain metastases, tumours of the thorax including non-small cell and small cell lung tumours, gastrointestinal tumours, endocrine tumours, mammary and other gynaecological tumours, urological tumours including renal, bladder and prostate tumours, skin tumours, and sarcomas, and/or metastases thereof.
Additionally, the compounds of the present invention show higher kinase inhibition selectivity and/or better performance in cellular assays than the MKNK inhibitors disclosed in prior art.